Radiation meter



T. E. FOULKE RADIATION METER Oct. 7, 1930.

Filed Sept. 11, 1926 INVENTOR S ATTORNEY Patented Oct. 7, 1930 UNITED STATES PATENT OFFICE TED E. FOULKE, OF NUTLE'Y, NEW JERSEY, ASSIGNOR T GENERAL ELECTRIC VAPOR LAMP COMPANY, OF HOBOKEN, NEW JERSEY, A CORPORATION OF NEW JERSEY RADIATION METER Application filed September 11, 1926. Serial No. 134,937.

[ purpose which utilizes that characteristic of certain glasses by which they affect radiations so that radiations of lower Wave lengths are produced. This characteristic is inherent for example, inherent in soda lead glass which '1 changes radiations in ultra violet and in the near ultra violet into a blue fluorescence. The invention further relates to means for comparing a standard light with the light produced from the invisible radiations for ob taining an arbitrary measure of the transformed light or fluorescence and thereby obtaining an arbitrary measure of the invisible radiations or of the source thereof.

Various other objects and advantages of 2 0 the invention will be obvious from the following particular description of one form of device embodying the invention or from an inspection of the accompanying drawings; and the inventionalso consists in certain new and useful features of construction and combinations of parts hereinafter set forth and claimed.

In the drawings accompanying and forming part of this specification, a practical com-. mercial embodiment of the invention is disclosed, but as such illustration is primarily for purposes of disclosure, it will be understood that the structure may be modified in various respects without departure from the 5 broad spirit and scope of the invention as hereinafter defined and claimed.

In the accompanying drawings there is shown for purposes of illustration one form of apparatus embodying the invention, in

0 which Fig. 1 is a longitudinal viewin part in mid-section, and with adjustable positions of movable parts indicated in dotted lines,

' Fig. 2 is a plan view of the device of Fig.

1 and Fig. 3 is an end view of one part taken at the line 3-3 of Pi 1. I

In the drawings t e tube 1 and tube 2 are fixed in position with respect to each other with their axes parallel, the tube 2 having one end intermediate the ends of tube 1 and having its other end extending beyond the corresponding end of tube 1. Tube 1 carries the tube 4 which slides lon itudinally therein, the bushing 6 fixed to tu e 1 and the bushing 8 fixed to tube 4 serving to guide tube 4 in its longitudinal movement and to limit such movement.

Said tube 4 carries on one side the longitudinal rack 10 to engage the pinion 12 which is on the outside of tube 1 but which extends through the longitudinal slot 13 toward tube 4 and which with said rack 10 serves to move tube 4 in tube 1, the thumb-piece 14 serving toimpart motion to the pinion. On its outer surface said tube 4 carries a positioning indicat-ing'scale 15', said tube being supported by bushing 6 through which it passes. At its outer 'end said tube 4 carries the tubular casing 16 withinwhich are mounted a rheostat 18, a rheostat control wheel20 and the ammeter 22,.the'ammeter being grounded on one side to said'casing 16 and being connected to said rheostat 18 at its other side. The other side of the said. rheostat 18 is connected to a contact 24 insulated from casing 16 and projecting into the interior of said tube 4. As illustrated said tube's'4 and 16 are of conducting material such as sheet .metal and areelectrically connected together.

screwed thereinto with the lamp positioned in the parabolic reflector. A central terminal of an electric cell 38 mounted within tube 4 makes electric contact with the other terminal of said lamp 36 which is of the regular screw socket type. Other dry cells 38 38 make contact in series from said cell 38 to said contact 24 in the manner well known in the flash light art. The casing 40 extends about the lamp end of tube 1, as distinguished from the ammeter. end thereof, v

and across to and about the end of said tube 2 which is intermediate the ends of said tube 1. Within said casing 40 there extends a passageway 42 from the inner or lamp end of tube 1 outwardly and transversely and then longitudinally alongside said tube 1 and to the inner endof said tube 2. In this side opposite said tube 1 said casing 40 has a longitudinal window 44 across which is mounted the sheet of glass 46 which has the characteristic of changing or causing the change of invisible radiations into visible radiations.

For example, such glass-suitable for this pur-' used.

' Said sheet 46 beside having a side exposed to said window 44 has also the edge 50 exposed toward the inner end of said tube 2. All the other edges of this sheet 46 are preferably covered or shielded as with the covering 52. Between said sheet 46 and the inner wall 54 of said casing is mounted the sheet of glass 56 which is of any suitable glass, but preferably in this case of soda lead glass, and which has an edge. 58 exposed to the interior of passage 42 and another edge 60 exposed parallel to edge 50 to the inner end of said tube 2. A pair of reflecting mirrors 62 and 64 mounted in said passage 42 at 90 to each other and at to the axes of the tubes 1 and 2 serve to reflect light passing from lamp 36 through window 28- to the edge 58 of the sheet 56 whereby there is emitted at said edge 60 a stream of light parallel to the visible radiations emitted at a said edge of sheet 46. For observation purposes said tube 2 carries an inner tube 66 which carries at its inner end the lens 68 and has as it outer end the peep-hole 70 and which is adjustable longitudinally in tube 2 to suit the vision of the observer.

In-the use of this embodiment of the invention, the standard lamp 36is brought to a given standard light intensity by adjusting rheostat 18 by a control member 20 to permit current of a given value to pass from said cells 38 38 thereof as indioated'by a standard reading on said ammeter 22. The glass sheet 46 is then pointed at a source of invisible radiations to be measured at a given distance therefrom, the said edges 50 and are viewed from the peep-hole to observe light transmitted from lamp 36 through sheet 56 and visible radiations produced in sheet 46 by the invisible radiations to which it is subjected. The intensity of the light at said edge 60 is varied to increase it or decrease it comparison with another reading made on scale 15 when the device is similarly used for matching light produced from the standardor other source of invisible radiations with which the one being measured is to be compared. The intensity of the fluorescence or visible radiations produced in soda lead glass by invisible radiations is directly proportional to the strength or intensity of the invisible radiations producing them and this is also true in other materials such as lime lead glass, these two intensities varying either directly or along known or determinable proportions or ratios. These ratios being known, useful comparisons and measurements can be made of invisible radiations with the device of the invention by observing well known laws of light transmission, that is, that the intensit of light varies inversely as the square of the distance from the source, etc.

Although I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will' be understood that various omissions, substitutions and changes in the use and in the form and details .of the apparatus illustrated may -be made by those skilled in the art without departing I claim: 1. In combination in .a meter forinvi'sible radiations, means for transforming invisible radiations into visibleradiatio'ns, havi a surface exposed for the'reception of invisible radiations and a surface at an angle thereto for the observation of the resulting visible radiations, means including a source for presenting a standard light for comparison with said visible radiations, and means for movin said source for varyingsaid standard ligt to match it with the said visible radiations. 2. In a meter for measuring invisible radiations, a longitudinal casing, a source of light in said casing and movable longitudinally toward and from a given end thereof, means for receiving and transferring the invisible radiations'into visible radiations and for presenting visible radiations to view comprising a receiving'surface and an observation surface at an angle thereto, means for presenting light. from said movable standard source for comparison with such said visibleradiations. 4 3. In a radiation meter, a longitudinal-- from the spirit of the invention.

tube, a standard source of light in said tube end thereof, a sheet of glass having the characteristics of transforming certain invisible radiations into visible radiations arranged with a given side for exposure to radiations to be measured and a given edge for observation and means for presenting a light from said standard source for comparison along said edge.

4. In a radiation meter, a longitudinal tube, a standard source of light in said tube and movable therein toward and from a given end thereof, a sheet of glass having the characteristics of'transforming certain invisible radiations into visible radiations arranged with a given side for exposure to radiations to be measured and a given edge for observation, means for shielding said edge from radiations passed to said side andmeans for presenting a light from said standard source for comparison along said edge.

5. In a radiationmeter a casing tube, a second tube slidable within said casing tube, a standard lamp mounted at one end of said inner tube, a plane reflector mounted across the end of said outer tube at an angle of tube mounted alongside of said sheet, a standard light in said tube and movable therein longitudinally, and reflectors arranged to receive light from said standardsource and to project it onto said second sheet, and means for moving said standard light in its tube and an arbitrary scale for indicating the position of said light in its tube, said standard .light being an incandescent electric lamp and means for bringing it up to a predetermined standard light intensity, comprising a battery of electric cells, a rheostat and an ammeter connected together.

TED E. FOULKE.

to its axis, a second reflector mounted to receive reflections from first said reflector and mounted at 90 to said first reflector and means for receiving and transforming invisible radiations into visible radiations and for presenting them to viewffor comparison with 7 sheet of glass having the characteristic of transforming invisible radiations into visible radiations, means for shielding all except one side and one edge of said sheet, a second sheet of glass mounted along the shielded side of said first sheet with an edge thereof parallel to said exposed edge, and means for passing a standard light through said second sheet and presenting it at said edge thereof for comparison with radiations emitted at the exposed edge of said first sheetcomprising a tube 'mounted alongside of said sheet, a standard light in said tube and movable therein longi tudinally, and reflectors arranged to receive light from said standard source and to project it onto'said second sheet, and means for moving said standard light in its tube and an arbitrary scale for indicating the position of said light in its tube.

7. In combination, in a radiation meter,

a sheet of glasshaving the characteristic of transforming invisible radiations into visible radiations, means for shielding all except one side and one edge of said sheet, a second sheet of glass mounted along the shielded side of said first sheet with an edge thereof. parallel to said exposed edge, a telescope for viewing both said edges, and means for passing a standard light through said second sheet and presenting it at said edge thereof for comparison with radiations emitted at the exposed edge of said first sheet comprising a 

